Surveyor&#39;s compass



May-18,1937. s. N. KouLlcHKov l`suRvEYoRs COMPASS Filed oct. 2o, 193e 2 sheets-sheet 1 Inventor'.-

May 13, 1937- l s lN. KouLlcHKv 2,080,776

SURVEYORS COMPASS 5,45 0 1,1 WM, MESH lllulilli Patented` May 18, 1937 UNITED STATES PATENT OFFICE Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

My invention relates to surveying Compasses and has particular reference to compasses or in- H'. struments for surveying in horizontal and vertical planes.

As is well known, in eld surveying with a compass, when running a closed traverse, it is seldom possible to close the traverse with an angular error within allowable limits, because the measurement of angles by a magnetic needle is accompanied by more or less large systematic errors. These errors are caused by magnetic variations l due to: local attractions of the magnetic needle 2O from the magnetic meridian, partly by daily deviations, (solar-diurnal variation), by the effect of static electricity under the glass cover of the compass housing, by the loss of magnetism of the needle (sluggish needle), Wear of the pivot '25 point under the needle, also a number lof other accidental causes, such as nearness of metal articles (axes, steel tape, chaining pins, tobacco cans, water pipe, high voltage transmission lines,

Y etc.). For the same reason it is often impossible to obtain satisfactory results when a magnetic compass is used for running a line on a certain bearing. Besides, the work with a compass requires extreme accuracy on the part of the surveyor, with an unavoidable loss of time while waiting for the cessation of the needle oscillations.

In order to overcome the above diliculties connected with the use of a magnetic compass, I devised an arrangement for direct measurement of angles without the use of a magnetic needle, which can be used only at the beginning of the surveying for orientation of the traverse. For this purpose I provide a special compass in which the sight vanes are not connected rigidily with the compass housing, but are mounted on a separate ring' which can be turned around on the housing and provided with a pointer for reading the angles on the upper compass scale; I also provide an arrangement for supporting an Abney level on the compass socket in order to simultaneously conduct surveying in a vertical plane, especially in connection with my specially calibrated surveyors rods, forming a subject of a separate patent application (Serial No. 37,929, filed August 26, 1935).

My invention is more fully described in the accompanying specication and drawings in which- 5 Figure 1 is a top plan View of my compass;

Figure 2 is a detail View of a sight ring in an open position;

Figur-e 3 is a detail View of a clamping screw for the ring;`

Figure 4 is a 'sectional view of the ring;

Figure 5 is an elevation of my compass with the Abney level;

Figure 6 is `a detail View of a clamp for the Y Abney level; 15

Figure 7 is an end view of the clamp; and,

Figure 8 is another view of the clamp.

Similar numerals refer to similar parts throughout the several views. y

My compass consists of a housing I for a mag- "2b netic needle 2 supported on a tubular stem 3 which lits over the end of a stem 4 and can be turned around on the stem in horizontal plane. A thumb screw 5 is used for clamping the compass. Y in any desired position on the stern. The stem has 25 a ball 6 fitted in a tripod socket l, which may be tightened to the tripod by an introduced set screw 35. Y

An upper or movable scale B of the compass is tightened by screws 9 so as to exactly corre- 30 spond to the lower scale I 0, but having the E and W points not interchanged. I prefer to use for arrangement a standard United States Forest Service campass, with changes and additions as will be described. 35

Standard sight vanes II and I2 in my device are mounted on a separate ring I3 consisting of two halves joined at one end by a hinge III and having a tightening and locking screw I5 at the other end. The screw I5 is screwed into the low- 40 er portion of one-half of the ring, and has a tapering upper portion I6 passing through a correspondingly tapered enlarged hole I'I in the upper or overlapping end of the other half of the ring. By tightening the screw its tapered portion 45 draws the halves 'of the ring together thereby tightening the ring on the compass housing. By turning the screw back the ring may be loosened sufciently to permitits turning around the housing. The heads of the screws 9 retain the ing 50 in its place on the housing. The ring is channeledon the inside as shown in Figure' 4, and flat springs I8 are fastened inside. These springs provide the necessary friction for the ring when it is being turned around so as to prevent its ao- 55 cidental slipping from a given position while taking the measurements of the angles. The pivot at the ring hinge and the tightening screw I5 have sharp index points I9 which serve as supplementary sights in order to lay ofi` the right angles to the readings taken through the main sight vanes II and I2, the latter being located at right angles to the supplementary sights. A thin pointer 3% attached to one of the sight vanes (with a hair) extends over the upper compass scale and is used for taking angle readings. The pointer fits into a corresponding slot in the sight vane when the latter is folded.

A bracket 20 is mounted under the compass on the tubular stem 3. The bracket has a hinged clamp 2| with a slot 22 on the end tting over a screw 23 and tightened by a nut 24. The screw is pivoted on the other end so that it does not need to be entirely removed When the clamp is turned out on its hinge for removing or replacing the bracket on the stern. The bracket and the clamp have elongated slots 25 for the screw 5 so that the bracket can be placed in various positions without interfering with the screw 5.

The bracket 2U has an extension 26 on which turns a sleeve 27 of a clamp 28 for an Abney level 29. The extension has a screw 30 in the end retaining the clamp 28 by its head which rests in a corresponding recess in the clamp. The clamp has a groove 3i for a screw 32 of the Abney level and a screw 33 for'clamping the Abney level in position. A clamping thumb screw 3d is used for setting the clamp with the Abney level in any desired position.

The operation of my device is as follows:

The movable or upper compass scale is set against the lower scale, or shifted as required for correction of the local declination, and tightened by a side screw 9. The pointer 36 (or the line of sight) must be coincided with the point of the stationary pin inside of the compass housing against the mark N. The sight vanes II and i2 are then placed against a base line by rotat- 'ing the compass box about its Vertical axis, and

the reading of the magnetic needle is noted (to orient the traverse to the magnetic meridian). From then on the needle is not used for further surveying. Without disturbing the compass frame I the ring I3 is turned directing the sight vanes against the next point on the traverse, and the angle is noted on the upper compass scale. The instrument is then moved to the next point and the ring is set so as to obtain the reverse bearing to the preceding point, the sight vanes being turned with the compass frame backward to the starting point. Then the angular reading to the next point is taken and these operations are continued until the traverse is closed.

Additional sights I9 may be used for taking readings at right angles to the direction in which the main sight vanes are set.

The Abney level, being held in a bracket, can give much more accurate readings than when held in the hands. In connection with my surveyors rod it can be used for accurate leveling and for various surveying measurements as described in my above mentioned patent application.

My device has the following important advantages:

1. It eliminates all the errors connected with the use of a magnetic needle, and therefore a1- lows more accurate surveys.

2. Aords considerable saving in time as it is not necessary to Wait every time for the needle oscillations to stop.

3. 'Ihe operations and computations are simplied due to the direct reading of the angles.

4. The layout of right angles to the given bearings are simpliiied and expedited.

5. The magnetic compass serves a much longer time.

6. Elevations are rapidly and accurately determined because of the stability of the mounting for the Abney level.

7. 'I'he Abney level can be used as a level for an accurate leveling with the use of my surveyors rod or an ordinary leveling rod.

8. The Abney level (its aperture) can be used for determination of distances by indirect method using my surveyors rod.

My device therefore can be used for various surveying operations eliminating the necessity of using a transit.

Having thus described my invention, what I claim for Letters Patent is:

l. In a surveying compass, the combination of a magnetic compass having a circular housing with stationary and movable scales and a stem base for mounting on a tripod, a ring rotatively mounted on the housing, sight vanes on opposite sides of the ring and attached thereto, a bracket removably mounted on the base, and means adapted to rotatively support a level on said bracket.

2. In a surveying compass, the combination of a magnetic compass having a circular housing with stationary and movable scales and a stem base for mounting on a tripod, a ring rotatively supported on the housing, sight vanes mounted on opposite sides of the ring, means to clamp the ring on the housing, and a pointer extending from one of the sight vanes to the movable scale on the compass.

3. In a surveyors compass, the combination of a magnetic compass having a stem base for mounting on a tripod, a bracket removably mounted on said base and extending transversely thereto, a clamp rotatively mounted on the end of said bracket, means to tighten the clamp on the end of the bracket, and means adapted to removably fasten a level in the clamp.

4. In a surveying compass, the combination of a magnetic compass having a stem base for mounting on a tripod and a circular housing with a stationary and movable scale, a ring rotatively mounted on the housing and consisting of two halves hingedly connected together, means to draw the ring halves together thereby tightening it on the housing, sight vanes mounted on opposite sides of the ring, and a pointer extending from one of the sight vanes to the upper movable scale on said compass.

5. A surveying compass as set forth in claim 2, characterized by resilient frictional means interposed between said ring and said housing.

SERGE N. KOULICHKOV. 

